A man was charged on Monday with attempting to blow up a Confederate statue in Texas.

The man, Andrew Schneck, was spotted by a ranger kneeling in the bushes near a statue of Confederate Maj. Richard Dowling on Saturday evening at Houston's Hermann Park.

The ranger reported seeing Schneck with two small boxes, according to the Department of Justice, and ordered him to put them down. Schneck allegedly complied, but then took a swig from a plastic bottle and immediately spat a clear liquid out.

That's when the ranger noticed a timer and wires in the boxes, federal prosecutors say.

Authorities believe Schneck had shown up with the materials needed to make a "viable explosive device," and on Monday charged him for attempting to damage the statue. According to the court documents, a white powdery substance police found at the scene proved to be hexamethylene triperoxide diamine, which the Justice Department describes as "an initiating, or primary explosive."

The clear liquid, the Justice Department said, was actually nitroglycerin.

"Nitroglycerin is highly dangerous to transport or use," the Justice Department said in a statement. "In its undiluted form, it is one of the world's most powerful explosives."

Court documents also state that Schneck had conducted "chemistry experiments" at his home in Houston.

The case comes amid an intense, and sometimes violent, debate about Confederate monuments in the US. Less than two weeks ago, a white supremacist rally in Charlottesville was organized to oppose the removal of a statue depicting Confederate Gen. Robert E. Lee. A woman ultimately died at that rally when a man drove his car into a crowd of counterprotesters.

Other monuments have since been removed by cities, universities, and even protesters. And multiple petitions have emerged calling for authorities to take down more Confederate monuments. Meanwhile, white supremacists and far right groups have mobilized to oppose the monuments' removal.

The statue of Dowling that Schneck is accused of trying to blow up was carved from white marble in 1905, according to the Hermann Park Conservancy. The Conservancy describes Dowling — who with a small group of men warded off an attempted Union invasion of Texas — as a "local Civil War soldier."

Schneck is facing federal charges because the statue is located in a park that received federal funding.

This is not the first time Schneck has faced charges related to explosives. In 2014, federal prosecutors charged him for storing explosive materials at a home in Houston. He eventually spent about two years on probation and had to pay a fine.

The penalty for trying to blow up a statue could potentially be much more severe. If convicted, Schneck now faces up to 40 years in federal prison and a $250,000 fine.